Saturday, May 02, 2009

Scientist finds slimming ingredient -- and other wonders -- in white tea

This study is NOT yet online at the alleged source but some details are given here. It was a purely in vitro study so its application to live people is unknown

Drinking tea could become a key weapon in the fight against obesity, research suggests. Scientists have found that white tea has special qualities that could help beat the bulge. The herbal tea - a more pure version of the black and green teas regularly consumed - has already been credited with a host of health benefits, from strengthening the bones to lowering blood pressure. Now tests have shown that compounds in the tea prevent the storage of fat and help break down existing stores.

Previously green and black teas have been found to block the absorption of cholesterol into the bloodstream. But it is thought that white tea, made from tender leaves and buds hand-picked from the top of the plant, may be more beneficial. The use of young, relatively unprocessed leaves helps retain high levels of the fatbusting compounds, the journal Nutrition and Metabolism reports.

Researcher Marc Winnefeld, of German skincare firm Beiresdorf, said: 'In industrialised countries, the rising incidence of obesity-related disorders including cardiovascular diseases and diabetes continues to be a growing problem. We've shown that white tea may be an ideal natural source of slimming substances.'

But the benefits come at a price. Up to 7,000 leaves picked by hand go into making just one kilogram of white tea, meaning it tends to cost around three times as much as everyday black tea. Bill Gorman, of the UK Tea Council, said: 'The production is very labour intensive, I don't think they will ever find a way of collecting it using machinery. 'It is an almost artisanal approach to making tea.' Mr Gorman added: 'The sales of speciality teas are growing at 25 per cent per annum. Tea is starting to do what wine did 30 years ago. 'People are interested in different varieties and countries of origin. 'I drink tea all day but near bedtime I generally have a cup of white or green tea. I find it refreshing at that time of night.'

To make a cup of white tea, it is recommended that a heaped teaspoonful of leaves are used for each cup. The leaves should be brewed for around three minutes, using hot, but not boiling water. If the the water is too hot it can bring out a bitter taste. However, the mild flavour of the tea means it is hard to over-brew it.

Britons drink their way through 48billion cups of tea a year. Fewer than a third take sugar but up to 98 per cent take milk. Ninety six per cent of all cups of tea made are brewed from teabags.

Previous research has suggested that drinking tea can cut the chance of ovarian cancer by a third.


Surprise, surprise! Genes 'have key role in autism'

Scientists have produced the most compelling evidence to date that genetics play a key role in autism. They highlighted tiny genetic changes that appear to have a strong impact on the likelihood of developing autism and related conditions. The changes influence genes which help form and maintain connections between brain cells.

The Nature study highlighted one common genetic variant in particular which, if fixed would cut cases of autism by 15%. Previously, other genetic variants have been linked to autism, but they are all relatively rare.

Dr Raynard Kington, of the US National Institutes of Health, which funded the research, said: "These findings establish that genetic factors play a strong role in autism spectrum disorder (ASD). "Detailed analysis of the genes and how they affect brain development is likely to yield better strategies for diagnosing and treating children with autism."

People with ASD, which include autism and Asperger's syndrome, have problems with social interaction, poor communication skills and tend to engage in repetitive behaviours.

In the latest studies researchers scanned the human genome for small differences between people who have an ASD, and those who do not. The largest study, led by the University of Pennsylvania, focused on more than 10,000 people. It found several genetic variants commonly associated with ASD, all of them pointing to two specific genes found on chromosome 5 which control production of proteins which help cells stick to each other, and make nervous connections.

One variant, linked to a gene called CDH10, was so common - present in over 65% of cases of autism - that the researchers calculated that fixing it would cut the number of autism cases by 15%. They also linked ASD rather less strongly to a group of about 30 genes which produce proteins that play a key role in enabling brain cells to migrate to correct places, and to connect to neighbouring cells. Other genetic changes pinpointed by the Pennsylvania team occurred in genes involved in a cellular waste system which probably ensures these "adhesion" proteins are kept in working order.

Lead researcher Dr Hakon Hakonarson said the genetics of ASD was likely to be complex. He said: "Because other autism researchers have made intriguing suggestions that autism arises from abnormal connections among brain cells during early development, it is very compelling to find evidence that mutations in genes involved in brain interconnections increase a child's risk of autism." But he added: "There are going to be many genes involved in causing autism. "In most cases, it's likely that each gene contributes a small amount of risk, and interacts with other genes and environmental factors to trigger the onset of disease."

Similar findings were reported in separate studies published in Annals of Human Genetics and Molecular Psychiatry. Professor Simon Baron-Cohen, an autism expert at the University of Cambridge, said 133 genes had now been linked to the condition, and much work was needed to piece together how they interacted with each other and the environment. He said: "The puzzle is slowly being pieced together, and the science of autism is accelerating in promising ways."

The National Autistic Society said the exact causes of autism were unknown. In a statement, the society said: "There is evidence to suggest that genetic factors are responsible for some forms of autism. "However, the difficulty of establishing gene involvement is compounded by the interaction of genes and by their interaction with environmental factors. "Various studies over many years have sought to identify candidate genes but so far inconclusively."


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